US1763279A - Metal rolling - Google Patents

Description

June 10, 1930.

J. B. TYTUS METAL ROLLING Filed June 20, 1925 OOOO E Bx

' being Patented June 10, 1930 UNITED STATES JOHN B. TYTUS, OF MIDDLETOWN, OHIO, ASSIGNOR TO THE AMERICAN ROLLING MILL PATENT OFFICE COMPANY, OF MIDDLETOWN, OHIO, A CORPORATION OF OHIO METAL ROLLING Application filed June 20,

My invention relates to processes and mechanisms for the purpose of reducing metal to sheet form whlle same is rendered soft by the application of heat. It relates particularly to continuous processes of rolling metal into sheets, by which I mean that the pieces rolled pass from one stand of rolls to anot er progressively after a single passage between the rolls.'

It is the object of my invention to provide for reduction of metal pieces individually to fairly thin condition and then to make packs of the pieces and continue the rolling still in a continuous manner.

In the rolling of heated metal sheets, there are two conditions of rolls employed, classed generally as hot and cold, the term used being hot mill and cold mill. What is meant by the appellation cold mill is a-mill the rolls of which are cooled by water and to the degree that water will adhere to their surface. In the cold mill some medium is employed for keeping the rolls cold, and in the hot mill, the metal itself heats up the rolls. In both hot and cold mills it may be desirable to appl hot and cold media to selected portions 0 the rolls, as by a gas flame, a shower of water, a blast of steam or air.

The advantage arising from the use of cold mills, is the elimination of distortion due to heating, which takes place in hot mills. Thus in hot mills the roller must make adj ustments to compensate for the rapid changes in dimensions due to change of relative temperature of different parts of the rolls, which occur as the result of highly heated pieces of material being passed between them, whereas these changes are eliminated in cold mills. The use of an individual stand of rolls for reducing packs of sheets to finished gauge requires the use of a hot mill, however, because in passing the piece back for repeated roll reductions its temperature would drop 'too much to permit of satisfactory working, if the rolls were kept cold.

In the drawing:

The figure is a diagram of a set of rolling mills, arranged in two groups.

In the diagram 1 is a furnace into which a slab of metal of predetermined width and 1925. Serial No. 38,436.

thickness, is fed, and as it emerges from the furnace is cut into pieces of predetermined length by shears located at 2. The stands of rolls 3, 4, 5, 6, 7, 7 and 7 are seven stands of rolls operated as cold mills. The rolls will preferably be supported in very rigid housings, and will be operated rapidly enough to eflect the desired reduction on the piece without intermediate reheating. The rolls run continually and the pieces pass from one stand to the next without stopping. Water pipes 8 provide sprays of water that keep the rolls cool and at a fairly uniform temperature. The mills 7, 7 a and 7 b are of more than two rolls, with one roll being of smaller diameter and backed up by alarger diameter roll. This type of mill may be used at other stations in the train, where greater degree of reduction per pass is desired.

When the individual pieces have been so rolled down to form the elements from which packs are to be made, they will be arranged one on top of the other to the desired number of thicknesses, and passed into the furnace 9. In order to permit of the individual pieces being diverted from pack rolling, I have not provided for continuous passage of the pieces from the rolls 7 to the furnace 9, or some intermediate doubling stage. Instead of this I have formed my furnace 9 in two sections,

will be used to heat the packs and the other section will be-used to bring the packs to a uniform temperature throughout. I also may send the individual pieces through furnace 9 and make my packs later. I prefer to make the packs of double length and shear them to correct size by the shears 10.

The rolls for reducing the packs to finished gauge are indicated at ll, 12, 13, 14: and 15, The mills will be cold mills, as in the first instance, and pipes 17 for sprinkling with Water are shown. Located close to the stands are small furnaces 16, which leave space for manipulating the packs between passes, to open them up and uide them into the next pass, if necessary. en the finishing mills are to be run cold, there must be provision for keeping the packs up to desired temperature The reason why hot mills have been used, in the past, in finishing packs of sheets or rolling plates into thinner sheets, is that the piece is passed back and forth inthe same stand of rolls, and if the mills are cold the pieces, by which term I include packs, will cool down too much, because of the small thickness. Thus it has been unheard of to try to roll packs of sheets in cold mills, and experienced rollers will pronounce this impossible to do with success.

I have found, however, that I can use cold mills in pack rolling, where I provide for suificient temperature control of the acks between stands, and particularly when roll the packs with the individual parts loosely related instead of tightly bound to each other. By terms loose and tight, the art refers to practice in rolling packs in which the pieces forming the packs, are either kept apart during each roll treatment and prevented from welding to ether, or in which the several pieces are xed together in the first roll action on the pack, and retained in fixed position, until the finishing passes have been completed. In either loose or tight packs, it is absolutely necessary to avoid a condition of partly stuck together and partly loose and hence some manual or mechanical manipulation will be required between stands in any event, so that space is required between stands to effect this manipulation.

I have further found that b running a mill of a number of stands of rol s, quite rapidly and providing individual pieces-of proper heat and size, that I am enabled at a single heating of cut sections of a heavy plate to reduce them to plate of proper thickness, for

making up packs, which may then be reduced, to form sheets of desired finished gauge, by means of a further series of cold mills, intermediate the several stands of which second series suitable heating devices are provided.

This permits me to roll finished sheets without use of hot mills. which eliminates several of the factors which have interfered with successful sheet rolling in a continuous manner in the past.

It has been found in practice that the packs will be reduced easil and will lie flat in each pass, with the pac moving continuously from one stand of rolls to the next.

By reducing the plate in a cold mill, the individual pieces from which the packs are made will be uniform for the runs of the mill, since distorting of rolls b overheating is not encountered. The rapi ity of the mill for individual plate reduction does away with the necessity for intermediate furnaces.

The packs are thus uniform for given runs, and the sheet rollers will be advised of the cross sectional shape of the packs on which theyi work. I

The settings, temperature and shape of the rolls in the finishing stands that operate on the packs, will be easier to control than in regular pack finishing on single stands of rolls. The necessary slowness of rolling, due to maintaining the pieces in open packs, and other exigencies of continuous pack rolling, require the presence of means to control the temperature of the packs in the several stands, said means being so arranged that they do not prevent the manipulation of the pack by the operators.

In order to attain a proper smooth rolling of thin plates and packs, and provide a natural tendency for the pieces to pass through the centers of the stands, I deliberately provide a convexity of the plates or packs. This convexity extends down the middle of the piece as it passes through the rolls. The activepass, i. e. the opening between the rolls when the plate or pack is in engagement, 1s so controlled as to be slightly less convex than the piece was before entering the pass. The original shape of the rolls is determined by the turning thereof; the nature of sprlng of the rolls during the active pass depends on the amount of screw that opposes the spreading of the rolls, the material diameter and length of the rolls, the width, thickness, composition and temperature of the piece. The temperature of the rolls in my present practice is not a variable feature. In general my cold process operates best with rolls which are so ground or turned as to have a slight crown at the middle, i. e., a slight taper from the middle down to the ends. This crown is made slightly less in the first stand of a series, than in the second stand and since the thinner the iece the less pressure is practical and there ore there is less springing of the rolls at the middle, the third and fourth stand, etc., may have the same crown as the second. The type of furnace in the pack mill is not essential, nor is it essential to use a furnace between every stand. On thick packs for example, I do not usually employ the furnace between the first two stands.

I do not wish myself limited to the use of all stands cold, however, as the insertion of one or more hot stands in the trains of roll stands would accomplish a portion of the advantages hitherto described by me, as attendant upon a continuous rolling process applied to thin wide material, in which cold mills are used preferably together with auxiliary heat controlling equipment as applied to the piece or pieces rolled also the type of roll stands whether two high or more than two high, can be varied without departing from my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A rocess for rolling heated metal in packs w ich consists in continuously passing the packs successively through stands of rolls,

which are kept cold.

2 A process for rolling metal into sheets which consists in reducing plate to pieces from which packs are to be made by passing plate sections through a series of stands of rolls successively, said rolls being maintained cold, at least in part, forming heated packs, and passing the packs successively through a serles of stands of rolls, said rolls also being maintained cold, at least in part.

3. A process for rolling heated metal in packs which consists in passing the packs through successive stands of rolls which are kept cold.

4. A process for rolling heated metal in packs which consists in continuously passing the packs through successive stands of rolls which are kept cold, and adjusting the temperature of the packs between selected stands.

5. A process for rolling heated metal in packs which consists in passing the packs successively through stands of rolls which are kept cold, and adjusting the temperature of the packs between selected stands, and manip ulating the packs between stands to assure the condition of the packs with relation to each other.

6. A process for rolling heated metal in packs which consists in continuously passing the packs through successive stands'of rolls which are kept cold, said packs being rolled oose.

7. A process for rolling metal into sheets which consists in reducing plate to pieces from which packs are to be made by passing plate sections through a series of stands of rolls successively, said rolls being maintained cold, forming heated packs and passing the packs successively through a series of stands of rolls, said rolls also being maintained cold. 8. A process for rolling metal into sheets which consists in reducing plate to pieces from which packs are to be made by passing plate sections through a series of stands of rolls successively, said rolls being maintained cold, forming heated packs, and passing the packs successively through a series of stands of rolls, said rolls also being maintained cold, and adjusting the temperature of the packs between the successive operations thereon.

JOHN B. TYTUS. 1

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